This invention relates to a urea formaldehyde (UF) resin modified with a water soluble non-ionic amine oxide. The modified resin has utility for increasing the tear strength of products prepared from glass fiber mats treated with the modified UF resin. This invention also relates to the further modification of the UF resin containing the amine oxide wherein such further modification includes the addition thereto of an anionic acrylic latex and/or a water soluble polymer of a polymerized ethylenically unsaturated carboxylic acid monomer whereby the tear property of the treated mat is significantly increased while maintaining the high level of tensile strength. The water soluble polymer comprises 40% to 100% by weight, based on polymer weight, of a polymerized ethylenically unsaturated carboxylic acid monomer wherein the polymer has a weight average molecular weight of from 100,000 to 2,000,000 and is also referred to herein simply as the water soluble polymer. The invention further relates to glass fiber mats impregnated with the modified UF resins, as well as roofing products and backing sheets for vinyl flooring utilizing the modified urea formaldehyde impregnated glass fiber mats. This invention also relates to a process for choosing the most desirable combination of binder and mat for manufacture of binder treated glass fiber mats.
Asphalt coated glass fiber mats are increasingly used as roofing shingles, replacing similar sheets traditionally made of wood or cellulose fibers. This type of glass fiber based roofing product has advantages such as in strength properties and in fire retardant characteristics.
Glass fiber mats are usually made by a wet-laid non-woven process somewhat similar to the paper making process. Examples of such processes can be found in U.S. Pat. Nos. 2,906,660; 3,766,003 and 3,838,995, each of which is incorporated herein by reference in its entirety. The wet-laid non-woven process for glass fiber mats can be described in the following stages:
The first stage involves forming an aqueous suspension of short length fibers under agitation in a mixing tank which is sometimes called the xe2x80x9cpulperxe2x80x9d. Glass fibers used in this application are generally about 0.5 to about 2 inches in length with typical diameters of about 3 to 20 microns. The glass fibers are also xe2x80x9csizedxe2x80x9d. Sizing is a process in which glass fiber manufacturing companies use proprietary chemistry and processes to provide various functions to the surface of the fiber. The functions are:
(A) As lubricants-coolants in the glass forming process while passing through the chopper to keep it dense;
(B) As moisture binding agents; and
(C) As aids to dispersion in the pulper.
The sizing process and sizing agents are also used to affect the physical properties of the glass fiber mats.
The short glass fibers come as strands or bundles and do not disperse well when mixed with water. In fact, upon prolonged agitation, the glass fibers agglomerate as large clumps which are difficult to re-disperse. Dispersion aids, usually surface active products, are used to facilitate the dispersion. High molecular weight polymers such as polacrylamide and hydroxyethyl cellulose are used to increase the viscosity of the media (water) in the pulper to help the suspension of the glass fibers. The dispersion of these glass fibers is critical for the formation of the mat.
The second stage of the process involves the formation of a glass fiber mat. The glass fiber dispersion in the xe2x80x9cpulperxe2x80x9d is further diluted with water, and passed through a mat forming machine. The fibers are collected on a moving wire screen in the form of a non-woven mat. Water is removed by gravity and, more often, by vacuum devices in the forming machine. The forming machine often moves at a speed of several hundred feet per minute. At the end of the second stage, the mat of glass fibers maintains its physical integrity and although it still contains water, there is little or no drippage of water from the mat.
During the process of mat forming, the wet mats need to be transferred from one section of the machine to another. Therefore, it is important that the mat has enough wet web strength to maintain its integrity during the non-woven wet laid process.
The third stage of this process involves binder application. Binders are applied to the moving mat by, for example, a falling film or curtain coater. After the binder application, the treated mats go through a de-watering device, which removes excess water to ensure a thorough application of binder throughout the glass fiber mat.
The fourth stage of the process involves the drying and curing of the glass fiber mats treated with binder. The treated mats are then passed through a series of ovens or other heating devices, usually at a temperature range of 200 to 250xc2x0 C. The binder treated mats are dried and the binder is cured when the mat passes through the ovens. The degree of curing or cross-linking of the thermosetting urea formaldehyde resin, along with its modifiers such as amine oxide, latex and/or water soluble polymers, affects the strength properties of the glass fiber mat. The interaction between the glass fiber surface and the binders during curing affects the distribution of the binder network and the glass fibers and therefore is important in determining the physical properties of the finished mats.
After the glass fiber mat has been formed and cured, it can be passed through a process which involves coating the mat with hot asphalt to form a roofing product such as roofing shingles. While the strength of the roofing product depends primarily on the strength of the mat, the tear property sometimes does not transfer fully to the roofing product.
Roofing products need to meet governmental and industrial strength requirements. The industry has successfully met the requirements in the past and has been able to optimize the tensile and tear properties. Recently, however, the need to withstand severe weather conditions caused a demand for further improvement in the tear property of the roofing shingles.
It is generally accepted that there is a balance between the tensile strength and the tear strength of the glass fiber mats. Processes in the prior art have provided an optimum balance between the tensile and tear properties which meet the earlier requirements. It is generally understood that the technical parameters in which the industry can work to obtain an increase in mat tensile also tends to lower tear strength. Therefore, it has been difficult to meet tear strength requirements without sacrificing the tensile strength. A simple solution to this problem is to increase the basis weight of the mat. However, this is a costly approach, and also provides an undesirable increase in the load of the shingles which the roof has to support.
Glass fiber producers have also tried to provide a solution by changing the sizing compositions and sizing technology. Recently these producers have developed fibers which provide high tear values or high tensile values to the glass fiber. These changes have not met the optimum requirement of the industry because of the following observations and reasons:
(1) The fiber either provides very high tensile strength and significant loss in tear strength or provides very high tear and substantial loss in tensile strength.
(2) The sizing chemistry has a significant effect on the distribution of the binder and fiber during curing. The effects of sizing changes can be so substantial that it makes it difficult to balance the desirable properties by sizing alone.
(3) A small amount of sizing material will dissolve into the white water during mixing and storage. This amount may be small, but when one looks at the very small amount of surfactant or dispersing agent used in the system, the amount of sizing material dissolved in the white water will significantly affect the white water chemistry and the dispersing of the fibers in the pulper.
Points (2) and (3) above are probably the reasons which make it difficult to optimize the tear and tensile strength by using only the sizing chemistry of the glass fibers.
U.S. Pat. No. 4,178,203 to P. Chakrabarti which issued on Dec. 11, 1979 discloses the use of amine oxide for increasing the dispersability of aqueous slurry of glass fibers in making glass fiber mats. After the mat is prepared, certain anionic surfactants are applied to the wet mat and eventually a binder is applied to the mat.
U.S. Pat. No. 4,183,782 to A. Bondoc which issued on Jan. 15, 1980 discloses the use of amine oxide and a derivatized guar gum to increase the dispersibilty of glass fibers in an aqueous slurry in the process of making a glass fiber mat. Eventually, a binder such as UF resin is applied to the mat.
U.S. Pat. No. 5,804,254 to P. Nedwick, et al. which issued on Sep. 8, 1998 discloses a method for flexibilizing a glass fiber non-woven bound with a cured urea formaldehyde resin binder wherein the binder includes a cured urea formaldehyde resin and 0.5% to 5% by weight, based on the weight of the urea formaldehyde resin of a water soluble polymer comprising 40% to 100% by weight, based on polymer weight, of a polymerized ethylenically unsaturated carboxylic acid monomer, the polymer having a weight average molecular weight from 100,000 to 2,000,000.
U.S. Pat. No. 5,914,365 to S. Chang et al. which issued on Jun. 22, 1999 discloses a binder composition containing UF resin modified with water soluble styrene-maleic anhydride copolymer for binding glass fiber mats. It also uses an aqueous slurry of amine oxide to disperse glass fibers. An example shows the use of UF resin modified with acrylic resin in comparison with the use of UF resin modified with styrene-maleic anhydride copolymer.
U.S. Pat. No. 5,965,638 to D. Heine which issued on Oct. 12, 1999 discloses a structural mat matrix, e.g., roofing shingle mat matrix, which consists essentially of: fiberglass fibers (80% to 90%); 20% to 1% of wood pulp; and a binder which consists essentially of UF resin; and from 20% to 5% of acrylic copolymer.
Although some of the above references show the use of amine oxide as a dispersant for the formation of the aqueous glass fiber slurry, the glass fiber mat at the time of application of the modified urea formaldehyde binder is substantially free of amine oxide, i.e., less than the amount needed to attain the advantageous tear properties shown by this invention. This is due to the solubility and high dilution of the amine oxide in the initial aqueous slurry, the usual addition of more water to the initial slurry and the drainage of water from the mat as it is being formed.
One object of this invention is to provide a process by which the binder described in this invention may be used with different types of glass fibers to provide an optimization of tensile and tear strength to non-woven glass fiber mats.
Another object of the invention is to provide a binder system which imparts the required improvement in tear strength to the glass fiber mat while maintaining an acceptable level of tensile strength.
Yet another object of the invention is the provision of increased tear strength and acceptable tensile properties to the coated asphalt roofing products. There have been cases wherein improvements in glass fiber mat strength do not represent an improvement in the roofing products due to the interaction of the binder treated mat with the asphalt coating process.
It has now been found that a binder composition comprising a urea formaldehyde(UF) resin modified with a water soluble non-ionic amine oxide provides improved tear properties to glass fiber mats. Also, the tensile strength of glass fiber mats treated with the modified UF resin can be improved with essentially no adverse effect on the improved tear property brought about by the modified UF binder by further modifying the UF resin with a latex and/or a water soluble polymer. Additionally, products, e.g., asphalt impregnated roofing products made from the bonded glass fiber mats maintain the desirable tensile and tear properties of the glass fiber mats. In addition to processes for producing the modified binder, bonded glass fiber mats and asphalt impregnated roofing products, this invention provides a process for choosing a combination of: (a) a modified UF binder for use with various glass fiber mats; or (b) various formulations within the bounds of the modified urea formaldehyde resin for use with glass fiber mats which provide substantially the same tear and tensile properties when substantially the same formulations are used. Such choosing or selecting is for the purpose of finding the combination of mat and binder or combination of formulation and mat for obtaining desirable tear and/or tensile properties in the bonded mats.
In one aspect, this invention is directed to a binder composition comprising a UF resin modified with a water soluble non-ionic amine oxide.
In another aspect, this invention is directed to a binder composition comprising a UF resin which has been modified with a water soluble non-ionic amine oxide and further modified with a latex and/or a water soluble polymer.
In still another aspect, this invention is directed to glass fiber mats which have been bonded with a binder composition comprising a UF resin which has been modified with a water soluble non-ionic amine oxide and optionally wherein such binder is further modified with a latex, a water soluble polymer, or both a latex and a water soluble polymer.
In yet another aspect, this invention is directed to a roofing product of an asphalt impregnated glass fiber mat bonded with a binder composition of a UF resin modified with amine oxide which may be further modified with latex and/or a water soluble polymer.
In a specific aspect of this invention, a glass fiber mat is made by the method comprising: dispersing glass fibers in an aqueous slurry; passing the slurry through a mat forming screen to form a wet glass fiber mat; applying a binder comprising a urea formaldehyde resin modified with a water soluble non-ionic amine oxide and optionally an acrylic latex and/or a water soluble polyacrylate; and curing the binder applied to the wet fiber mat.
In yet a further aspect, this invention is directed to processes for the manufacture of the above binders, glass fiber mats bonded with the above binders and asphalt impregnated glass fiber mats bonded with the above binders.
In but a still further aspect, this invention is directed to a process for obtaining desired or improved tear and at least equal or improved tensile properties in a glass fiber mat by choosing glass fiber mats for manufacture into mats bonded with a UF binder composition of this invention from glass fiber mats which may have differing chemical and physical properties and consequently provide different values of tensile and tear strength to a mat bonded with said binder composition. The process comprises:
(A) testing various glass fiber mats bonded with the UF binder to determine their tensile and tear properties;
(B) choosing glass fiber mats, or glass fibers for manufacture into mats, which provide the desirable tear and tensile strength for binding into mats with said binder; and, optionally
(C) using glass fiber mats having substantially the same chemical and physical properties as the mats which provide the desirable tear and tensile strength for production of additional mats bonded with said binder.
In but yet a still further aspect, this invention is directed to a process for choosing a formulation of a urea formaldehyde binder composition of this invention from differing formulations of said urea formaldehyde binder for binding glass fiber mats wherein the various formulations of said binder provide different values of tensile and/or tear strength to said glass fiber mat bonded with said binder in order to obtain a desirable combination of tear and tensile strength in the glass fiber mat, said binder formulations being that of a urea formaldehyde resin modified with a water soluble non-ionic amine oxide and a member selected from the group consisting of a latex, a water soluble polymer and both a latex and a water soluble polymer wherein the quantity of the amine oxide and the presence of one of said members and/or the amounts of such members in the formulation differ, said process comprising the steps of:
(A) testing various formulations of said binder differing in the amount of amine oxide, the presence or absence of either the latex or water soluble polymer and the amounts of said latex or polymer in the formulation wherein said tests are conducted on glass fiber mats which provide substantially the same tear and tensile properties when substantially the same formulation is used in order to determine the tear and tensile strength of the glass fiber mats after application of the various formulations;
(B) choosing the formulation which provides the desirable tear and/or tensile strength for binding the said fiber mats; and optionally
(C) using the formulation which was chosen in (B) above for the further production of said glass fiber mats bonded with the chosen formulation.
Methods for preparation of the thermosetting UF resin which may be used in this invention are known to those skilled in the art. Commercially available UF resins sold to the glass fiber mat industry by Borden Chemical, Inc, and Georgia Pacific Resins Corp., for example, are suitable for use in this invention.
UF resins are generally optimized during their manufacture by adding polyalkylenepolyamines such as triethylene tetramine, tetraethylenepentamine as well as ammonium hydroxide to provide charge characteristics as well as to moderate the subsequent curing rate of the resin. The amount of polyalkylenepolyamines used in the manufacture of the UF resin will generally vary from about 0 to 3% and preferably about 0.002 to about 1% by weight of the UF resin. The amount of aqueous ammonia used in the manufacture of the UF resin will generally vary from about 0% to about 20% of 26 Baume ammonia based on the weight of the UF resin and preferably about 3 to about 12%. The UF resins as well as the modified UF resins used in this invention will generally have a pH of from about 7 to about 8.5, a Brookfield viscosity of from about 50 to 500 cps, a free formaldehyde level of about 0 to 3% and preferably about 0.1 to 0.5%, about 45% to about 65% or 70% of non-volatiles, and a water dilutability of about 1:1 to 100:1, preferably 10:1 to 50:1.
The molar ratio of formaldehyde to urea of the UF resins used in this invention can vary over a wide range such as that of from about 1.4 to about 3.0. A preferred molar ratio of formaldehyde to urea in the UF resin is about 1.4 to about 2.4. A typical modified UF resin of this invention has a non-volatile content of about 55%, a pH of about 8 and a viscosity (Brookfield LVF #2/60 rpm, at 25xc2x0 C.) of about 250 cps.
The phrase xe2x80x9chigh tear binderxe2x80x9d as used in this application refers to a UF resin which has been modified with an amine oxide and further modified with a latex or a water soluble polymer or both a latex and water soluble polymer. All of the modified UF resins contain amine oxide but they may or may not contain the latex and/or water soluble polymer.
The high tear properties imparted to the urea formaldehyde (UF) resin involve the addition to a UF resin of a non-ionic water soluble or dispersable amine-oxide surfactant. The general structure of the amine oxide surfactant can be represented by the following formula: 
wherein each of R1, R2, and R3 are hydrocarbon groups containing from 1 to about 30 carbon atoms. The hydrocarbon groups can be aliphatic or aromatic, and, if aliphatic, can be linear, branched or cyclic in nature, and can be the same or different in each radical. Aliphatic groups are preferred. The aliphatic hydrocarbon radical can contain ethylenic unsaturation. Preferably the aliphatic groups are selected from among alkyl groups such as lower alkyl or hydroxyalkyl groups having from 1-4 carbon atoms and substituted alkyl groups thereof, or long chain alkyl groups having from 12 to 30 carbon atoms such as stearyl, lauryl, oleyl, tridecyl, tetradecyl, hexadecyl, dodecyl, octadecyl, nonadecyl or substituted groups thereof. The sum of the various R groups normally have about 14-40 carbon atoms and particularly 18-24 carbon atoms.
The quantity of amine oxide used to make the modified UF resin of this invention is in an amount sufficient to improve the tear property of a glass fiber mat. Thus, the concentration of the amine oxide in the modified UF resin can vary over a broad range such as that from about 0.01% to about 1%, preferably about 0.05% to 0.2% and particularly about 0.1% to about 0.15% based on the weight of the modified UF resin, i.e., the UF resin together with the modifier or modifiers of this invention.
The amine oxide is preferably added at the end of the UF polymerization. However, the amine oxide can be added to the UF resin at any time such as during the polymerization reaction of the urea with the formaldehyde in the manufacture of the UF resin or afterwards. The addition of the amine oxide, such as by mixing and blending in the UF resin under ambient conditions, modifies the resin to produce a modified UF resin. The further addition of the latex and/or water soluble polymer, again such as by mixing and blending, further modifies the resin to produce the high tear binder. The order in which the modifiers are added to the resin is not important although it is preferred that the amine oxide be added first.
Commercial examples of amine oxides which can be used in this invention include those sold by Akzo Nobel such as: Aromox DM 16 which contains dimethylhexadecylamine oxide, Aromox C/12 which contains a mixture of N-coco alkyl-2,2xe2x80x2-iminobis-ethanol-N-oxide, Aromox T/12 which contains bis(2-hydroxyethyl)tallowamine oxide; Aromox DMC which contains dimethylcocoamine oxide; and Aromox DMHT which contains dimethyl(hydrogenated-tallow)amine oxide. Of course amine oxides having the same chemical structures and supplied by other chemical companies are also suitable.
The purpose of adding a suitable latex modifier in this invention is to provide an enhancement to the tensile property of the amine oxide modified UF resin. The latex increases tensile without affecting the high tear property of the amine oxide modified UF resin. An example of a preferred latex is an anionic acrylic latex marketed by Rohm and Haas Company under the trade name Emulsion E2321. This latex is a very firm binding agent used as an additive to stiffen hand in fabric finishing operations. It has good wash/dry-cleaning durability and abrasion resistance. Its glass transition (Tg) temperature is 105xc2x0 C. It is packaged at pH 7.5 and the Brookfield viscosity is 50 cps at about 45% solids.
The quantity of latex used in this invention is in an amount sufficient to improve the tensile property of a glass fiber mat. Thus, the latex can generally be used at a concentration of about 0.1% to about 25%, preferably about 2% to 20% and particularly about 6% to 15% based on the weight of latex as a percentage of the weight of the UF resin containing the latex together with any of the other modifiers. Preferably, the latex is added and thoroughly mixed with the UF resin at any time after the completion of the urea and formaldehyde polymerization reaction and at a pH of about 7 to about 8.5.
Anionic acrylic and vinyl acrylic latices can be used in this invention. Preferably such latices have Tgs (glass transition temperatures) between about 25xc2x0 C. to about 110xc2x0 C. Also, it is preferred that such latices have self -crosslinking capacity. Examples of suitable commercial latices for use in this invention include: the above mentioned Emulsion E2321, Rhoplex OP 62 and Rhoplex Exp 3360 which are supplied by Rohm and Haas Chemical Company; CPD 3102 series, supplied by Sequa Chemicals, Inc; Convinex 380 and Convinex JW 215 supplied by Franklin International, and PD 8168 series of latex which have a Tg at about 100xc2x0 C., as supplied by Fuller Chemical Company can be used. The acrylic latex can be based on polymers or copolymers produced from monomers comprising ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid and esters of these monomers such as methylacrylate, methylmethacrylate and cross-linkable functional comonomers, for example, but not limited to, methylol-acrylamide. The vinyl acrylic latex is a copolymer of an acrylic monomer, e.g., an acrylate monomer and a vinyl monomer. Illustrative of acrylate monomers there can be mentioned those represented by the following structure: 
wherein C, H, and O represent carbon, hydrogen and oxygen and R1 and R2 are alkyl groups. Depending on the choice of R1 and R2, polymers or copolymers of the acrylate having different hardness and Tg values can be prepared. The preferred vinyl acrylate polymer is that of an acrylate and vinyl acetate which generally produces a hard polymer.
The water soluble polymer contains 40-100% by weight, based on polymer weight, of at least one polymerized ethylenically unsaturated carboxylic acid monomer. The water soluble polymer is formed by polymerization of ethylenically unsaturated monomers such as, for example, methacrylic acid, acrylic acid, crotonic acid, fumaric acid, maleic acid, 2-methyl maleic acid, itaconic acid, 2-methyl itaconic acid, a,b-methylene glutaric acid, and salts thereof. Alternatively, ethylenically unsaturated anhydrides which form carboxylic acids during or subsequent to polymerization may be used in the polymerization such as, for example, maleic anhydride, itaconic anhydride, acrylic anhydride, and methacrylic anhydride. Additional ethylenically unsaturated monomer(s) may be copolymerized with the carboxylic acid monomer in an amount of 0-60% by weight, based on polymer weight, such as, for example, acrylic ester monomers including methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, and hydroxypropylmethacrylate; acrylamide or substituted acrylamides; styrene or substituted styrenes; butadiene; vinyl acetate or other vinyl esters; acrylonitrile or methacrylonitrile; and the like. The optional additional ethylenically unsaturated monomer must be selected so as not to render the polymer insoluble in water; thus, only lesser amounts of hydrophobic monomers may be used while greater amounts of hydrophilic monomers ma be used without compromising water solubility of the polymer. The water soluble polymer has a weight average molecular weight from 100,000 to 2,000,000, as measured by aqueous gel permeation chromatography. The water soluble polymers which are used in this invention as well as their method of preparation are described in greater detail in U.S. Pat. No. 5,804,254 of Sep. 8, 1998 to P. Nedwick et al. which is incorporated herein by reference it its entirety. When the water soluble polymers are used in this invention it is preferred that they be neutralized to a pH of about 7 to about 11 and preferably to a pH of about 8 to 11. Conventional alkaline materials can be used for neutralizing the polymers such as that of ammonia, ammonium carbonate, as well as alkali metal or alkaline earth metal hydroxides and carbonates such as those of sodium, potassium and calcium.
A water soluble polymer can be used in conjunction with or instead of the latex modifier in this invention in preparing the high tear binder. An ammonia neutralized polyacrylate solution polymer marketed by Rohm and Haas Company under the trade name Solution HS 100 is an example of a water soluble polymer which can be used in this invention. It also finds uses for thickening and stabilizing water based synthetic and natural latices. Solution HS 100 is a clear to slightly hazy liquid usually shipped at 11% solids at a pH of 9.3. It has a Brookfield viscosity of about 700 cps. It also finds uses for thickening and stabilizing water based synthetic and natural latices.
The addition of the water soluble polymer as well as the latex is generally made after the manufacture of the UF resin either before, after or at the same time as the addition of the amine oxide to the UF resin. Preferably they are added after the addition of the amine oxide. The water soluble polymer can be used in the amine oxide modified UF resin, with or without the use of the latex.
The quantity of the water soluble polymer used in the binder compositions of this invention is in an amount sufficient to improve the tensile property of a glass fiber mat. The quantity of water soluble polymer used in the modified UF resin can vary over a wide range such as that of about 0.1% to about 5% and preferably about 0.2 to about 3% based on the weight of the modified UF resin. Ammonia neutralized polyacrylate solutions with a range of molecular weight as represented by Brookfield viscosities between 400 to 1000 cps at 11% solids are preferably used as the water soluble polymer in this invention.
When both the acrylic latex and water soluble polymer are used in the high tear binder, the quantities of each can be such as those given hereinabove for each of the latex and water soluble polymer, although it is preferred that the total quantity of the these two modifiers not exceed about 25% based on the weight of latex plus water soluble polymer in relation to the weight of the UF resin modified with the amine oxide, latex and water soluble polymer.
The amount of binder applied to the glass fiber mat in this invention is in an amount sufficient to attain desired tear and/or tensile properties. Thus, this quantity can vary over a wide range such as that of loadings in the range of about 3 to 45 percent by weight, and preferably about 10 to 40 percent by weight of non-volatile binder composition based on the dry weight of the bonded mat.
The modified UF resin of this invention can be applied to a wide variety of glass fiber mats since the chemical and physical properties resulting from prior treatment of the fibers and mats such as sizing, suspending agents and the various other processes and compositions used to make the fiber and mat are substantially less critical to the tear and tensile properties imparted to the glass fiber mat by the high tear binder as compared to other UF binder compositions for improving tear and/or tensile in glass fiber mats. Nevertheless, certain binders of this invention in combination with certain glass fiber mats will provide the more desirable tensile and tear properties. Also, certain formulations of the binder of this invention in combination with certain glass fiber mats will provide the more desirable tensile and tear properties. In this respect however, those mats from fibers which provide very high tear strength accompanied by a substantial loss of tensile strength are not recommended for use in this invention.
The applicability of the high tear binder to glass fiber mats having different chemical and physical properties is unusual since conventional UF binders used on mats are limited as to their ability to improve the tensile and tear of mats having differences in chemical and physical properties. Since applicants"" high tear binder is suitable for improving the tear and tensile properties of glass fiber mats having a broad range of chemical and physical properties, and further since some combinations of binder and mat show optimal or improved properties, the binders of this invention can be used in testing various mats in order to choose mats having desirable properties. The production of additional mats bonded with the binder can then proceed by using glass fiber mats having substantially the same physical and chemical properties as those having the chosen desirable tear and tensile properties. Desirable properties can include different criteria such as tear strength, tensile strength, or combinations of tear and tensile strength. Choosing a particular formulation of a binder of this invention for use with glass fiber mats exhibiting similar tear and tensile properties in order to obtain desirable tear and/or tensile properties can also be done by such testing and choosing since the binder of this invention can use a broad concentration of modifying agents and include or eliminate the latex or water soluble polymer to provide the more desirable tear and tensile properties. The production of glass fiber mats of substantially the same chemical and physical properties can then proceed with the use of the chosen formulation.